Conventional golf balls designs include solid and wound configurations, with the majority being of solid construction. Solid golf balls can include one-piece, two-piece (i.e., solid core and a cover), and multi-layer (i.e., solid core of one or more layers and/or a cover of one or more layers) golf balls. Wound golf balls typically include a solid, hollow, or fluid-filled center, surrounded by a tensioned elastomeric material, and a cover.
Golf ball core and cover layers are typically constructed with polymer compositions including, for example, polybutadiene rubber, polyurethanes, polyamides, ionomers, and blends thereof. Ionomers, particularly ethylene-based ionomers, have become a common choice of polymers for golf ball layers because of their toughness, durability, and wide range of hardness values.
Ionomers can be stiffened by increasing the amount of neutralization. Neutralization to 70% and higher, including 100%, has been disclosed. However, in the absence of flow additives, at neutralization levels above about 60%, the melt flow of the ionomer is decreased to an extent such that processability decreases or disappears altogether. For trivalent cations, the percent neutralization at which the polymer becomes unprocessable, in the absence of flow additives, can be significantly lower. Frequently, flow additives can include fatty acids or their salts.
Although improvements in processability and golf ball properties have been achieved, the options for flow additives is limited and usually come with compromises such as discoloration, surface blooming and coating adhesion to name a few. Therefore, new polymer compositions and components continue to be sought for use in forming golf balls.